Bla Bla Bla Analogy Bla bla
Well then, my advice for you is to NOT buy the expansions and simply play the original game. The original game is fully fuctional (except for multiplayer during release) and with the latest patch it will be as polished as it will ever be. If you want the developers to cover 'Everything' then this game would be released in maybe 5+ years time, cost maybe 100+ US dollars and cause the company to collapse as no one wants to fork out that much money for a 'Complete' game.
The expansions are expansions, they add on EXTRAs, so its not a life and death matter if you want to buy them or not. Look at all the other RTS around, Brood War, Frozen Throne, Forged Alliance, Opposing Fronts and so forth, why did These developers not release their original games 1-2 years late with the expansions in them? and cost maybe 60-90 US dollars. Because its simply not viable and people will not fork out that much money just for a 'Uber' game. People prefer 'tasters' and like expansions to build up from the previous game.
Games are 'luxuries' you don't need to buy em if you don't need em and in this case, who is forcing you to buy the expansions as stated in your post? You don't need em to enjoy Sins. Oh and if you want a 'Solid' expansion, buy all three expansions at once then when they are all finally released...................for the same price as buying them seperately
P.S. If you want a Car analogy, you got a perfectly fine car with Sins and the 3 expansions are simply adding a More powerful engine, NOS and better wheels. (You don't get em for free either in the real world........)